Jaywick Martello Tower was built in 1809 and was originally one of twenty-nine Martello towers situated on the east coast of England. The towers were constructed to defend the country against the threat of invasion by Napoleon Bonaparte and his armies. In total, 103 Martello Towers were built between 1804 and 1812. Seventy-four were built between 1804 - 1808 along the Kent and Sussex coastlines from Folkestone to Seaford, and twenty-nine were constructed along the east coast between Point Clear near St Osyth and Aldburgh from 1808 - 1812. The south coast towers were numbered 1 – 74, while the east coast towers were lettered A – Z. Three additional east coast towers are known as AA, BB and CC.

The bricks for the east coast towers were made at Grays in Essex using London Clay and transported to each site by barges. The brick walls of the east coast Martello Towers are 2 to 3 metres thick (between 8-12 feet) and they are about 10 metres (40 feet) high. The east coast towers were constructed with approximately 500,000 bricks; the smaller South Coast towers were built with around 250,000 bricks. The south coast towers were equipped with one cannon on each roof, while the east coast towers boasted three: usually a 24-pounder facing out to sea and two smaller Howitzers at each side.

The name ‘Martello’ is derived from a similar military sea defence tower at Mortella Point in Corsica, near Italy. By 1793, the French had occupied Corsica and the Mortella tower was being used by the French Navy to bombard any ships that tried to seize the island. The Corsican people asked the British Government for help and two battleships were sent to take the tower the following year. On 9 February 1794 it was finally captured by the British after two days of fighting. The Mortella Tower had withstood the combined force of 101 cannons being fired from two English battleships during this time and was only defeated after a fire broke out inside the tower. The British Navy were so impressed with the strength of the tower that before they left Corsica they took its measurements, which formed the basis for the size and shape of all our English Martello Towers.